"And 'snow' will finally melt, and disappear".
More spikes than in the normal mode, and one save was removed. It looks good in the game, because the extra spikes are blue, not red, and they are nicely placed, transforming the game into a good advanced needle game.
If the normal mode isn't enough for you, this is a good way to enjoy the game while getting more challenge. Also, you'll need to clear this mode if you want the second ending.